Armored power cable installed in coiled tubing while forming

ABSTRACT

An electrical submersible well pump assembly includes a pump driven by an electrical motor. A string of tubing connects to the well pump assembly and extends to an upper end of a well. A power cable installed in the tubing has three insulated electrical conductors embedded within an elastomeric jacket. A metal strip has turns wrapped helically around the jacket. The metal strip is compressed between the jacket and the tubing to cause the power cable to frictionally grip the tubing.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to provisional application 62/037,972,filed Aug. 15, 2014.

FIELD OF THE DISCLOSURE

This disclosure relates in general to electrical submersible pumps forwells and in particular to an armored power cable installed withincoiled tubing while the coiled tubing is being formed.

BACKGROUND

Electrical submersible pumps (ESP) are often used to pump fluids fromhydrocarbon wells. An ESP includes a motor, a pump, and a seal sectionthat reduces a pressure differential between well fluid on the exteriorand dielectric lubricant in the motor interior. An ESP may have othercomponents, such as a gas separator or additional pumps, seal sectionsand motors in tandem.

A power cable extends from the surface to the motor for supplyingthree-phase power. Usually, the power cable has three conductors, eachof which is separately insulated. A single elastomeric jacket isextruded over the three insulated conductors. A metal strip or armorwraps around the jacket. In round cable, the exterior of the jacket iscylindrical in cross-section. In some installations, a tube extendsalongside the armor of the power cable. The tube may be used to conveyliquids, or the tube may have an instrument wire located inside. It isknown to wrap the tube and the armor together with another metal strip.

In most cases, a string of production tubing supports the ESP, and bandssecure the power cable to and alongside the production tubing. When theESP has to be retrieved for repair or replacement, a workover rig isrequired to pull the tubing along with the power cable and ESP.

It is desirable to avoid having to employ a workover rig to retrieve theESP. However, a conventional power cable cannot support its own weightin many wells, thus needs additional support. One technique involvesplacing the power cable within coiled tubing, which is a continuouslength of metal tubing deployed from a reel. The pump discharges up anannular space surrounding the coiled tubing.

Various methods have been proposed and employed to transfer the weightof the power cable to the coiled tubing. In one method, the power cablewith armor is pulled through the coiled tubing after the coiled tubinghas been formed. Various standoffs or dimples formed in the coiledtubing engage the armor to anchor the power cable within the coiledtubing. In another method, the power cable without an armor is placed inthe coiled tubing as the coiled tubing is being formed and seam welded.

SUMMARY

An electrical submersible well pump assembly includes a pump driven byan electrical motor. A string of tubing connects to the well pumpassembly and extends to an upper end of the well. A power cableinstalled in the tubing has three insulated electrical conductorsembedded within an elastomeric jacket. A metal strip has turns wrappedhelically around the jacket. The metal strip is compressed between thejacket and the tubing to cause the power cable to frictionally grip thetubing.

Each of the turns of the metal strip overlap with adjacent ones of theturns. Preferably, when viewed in a transverse cross section, each ofthe turns of the metal strip has a generally S-shaped configuration,defining an outward facing curved valley and an inward facing curvedvalley, relative to a centerline of the power cable. The inward facingcurved valley of each of the turns of the metal strip overlaps theoutward facing curved valley of an adjacent one of the turns.

Each of the outward facing and inward facing curved valleys has an edgeat a margin of the metal strip. The edge of the inward facing curvedvalley may be in contact with an outer surface of the outward facingcurved valley. The edge of the outward facing curved valley may be incontact with an inner surface of the inward facing curved valley.

Preferably, the metal strip is elastically deformed between the jacketand the tubing. Prior to installation of the power cable in the tubingand after the metal strip is wrapped around the jacket, the metal striphas a radial dimension between an inner side and an outer side that isgreater than the radial dimension of the metal strip after installationof the power cable in the tubing.

The power cable may have at least one tube embedded within the jacketalongside the conductors and extending along a length of the powercable. Multiple tubes may be embedded is the jacket and symmetricallyspaced relative to a centerline of the power cable. The tube may housean instrument wire or it may be used to convey fluids.

Alternately, the tube may extend alongside and exterior of the jacket.If on the exterior of the jacket, each turn of the metal strip extendsaround the tube and the jacket. The power cable may have an inner armorstrip wrapped helically around the jacket with the tube located exteriorof and in contact with the armor strip. The metal strip wraps around theinner armor strip and the tube.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features, advantages and objects of thedisclosure, as well as others which will become apparent, are attainedand can be understood in more detail, more particular description of thedisclosure briefly summarized above may be had by reference to theembodiment thereof which is illustrated in the appended drawings, whichdrawings form a part of this specification. It is to be noted, however,that the drawings illustrate only a preferred embodiment of thedisclosure and is therefore not to be considered limiting of its scopeas the disclosure may admit to other equally effective embodiments.

FIG. 1 is a schematic view of an electrical submersible pump assemblysupported by coiled tubing containing a power cable in accordance withthis disclosure.

FIG. 2 is a transverse cross sectional view of the power cable withincoiled tubing of the pump assembly of FIG. 1.

FIG. 3 is a longitudinal cross sectional view of a portion of the powercable and coiled tubing of FIG. 2, taken along the line 3-3 of FIG. 2.

FIG. 4 is schematic view of the coiled tubing being formed and weldedaround the power cable of FIG. 2.

FIG. 5 is a longitudinal cross sectional view of the power cable beingformed in FIG. 4, after welding and before swaging.

FIG. 6 is a transverse sectional view of an alternate embodiment ofpower cable within coiled tubing.

FIG. 7 is a transverse sectional view of another alternate embodiment ofpower cable within coiled tubing.

DETAILED DESCRIPTION OF THE DISCLOSURE

The methods and systems of the present disclosure will now be describedmore fully hereinafter with reference to the accompanying drawings inwhich embodiments are shown. The methods and systems of the presentdisclosure may be in many different forms and should not be construed aslimited to the illustrated embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey its scope to those skilled in the art.Like numbers refer to like elements throughout.

It is to be further understood that the scope of the present disclosureis not limited to the exact details of construction, operation, exactmaterials, or embodiments shown and described, as modifications andequivalents will be apparent to one skilled in the art. In the drawingsand specification, there have been disclosed illustrative embodimentsand, although specific terms are employed, they are used in a genericand descriptive sense only and not for the purpose of limitation.

Referring to FIG. 1, the well includes casing 11, which will be cementedin place. In the embodiment shown, a tubular liner 13 extends throughthe casing 11. Liner 13, which serves as production tubing, is of aconventional type, having sections secured together by threads. Liner 13is not cemented in the well. An electrical pump assembly (ESP) 15 issupported inside liner 13. A packer 17 supports ESP 15 in liner 13 andseals the annulus around ESP 15. Typically, ESP 15 has a stinger (notshown) on its lower end that slides into a polished bore in packer 17.

ESP 15 includes a centrifugal pump 19 of conventional design.Alternately, pump 19 could be another type of pump, such as aprogressing cavity pump or a linear reciprocating pump. In this example,pump 19 has a lower end located below packer 17. Pump 19 has intakeports 21 below packer 17 and discharge ports 23 located above packer 17for discharging well fluid pumped from the well. Packer 17 seals theannulus between ESP 15 and liner 13, and pump 19 draws well fluid frombelow packer 17 and discharges it into the annulus above packer 17.

An electrical motor 27, normally a three phase type, is coupled to aseal section 25, which in turn connects to pump 19. Seal section 25 hascomponents to reduce a pressure differential between lubricant containedin motor 27 and the well fluid. A shaft (not shown) extends from motorthrough seal section 25 and into pump 19 to rotate pump 19. The upperend of motor 27 has an adapter (not shown), which may be of varioustypes, and serves as means for securing ESP 15 to a lower end of alength of coiled tubing 29.

Coiled tubing 29 contains a power cable 31 for motor 27 and alsosupports the weight of power cable 31 and ESP 15 while ESP 15 is beinglowered into the well. Although motor 27 is shown mounted above sealsection 25 and pump 19, the assembly could be inverted with motor 27 atthe lower end.

Coiled tubing 29 is metal, flexible tubing of a type that will be coiledon a reel (not shown) located at the surface before ESP 15 is deployed.A production tree 33 at the upper end of casing 11 provides pressure andflow control. A flow line 35 extends from tree 33 for delivering wellfluids pumped by ESP 15. Production tree 33 provides support for theupper end of coiled tubing 29.

Referring to FIG. 2, power cable 31 includes three electrical conductors37 for delivering power to motor 27. Each conductor 37 is ofelectrically conductive material, such as copper. At least oneelectrical insulation layer 39 surrounds each conductor 37. Insulatedconductors 37 are twisted about each other along a power cable centerline 38. At any point, when viewed in a transverse cross-sectionperpendicular to power cable center line 38, insulated conductors 37will appear oriented 120 degrees apart from each other. The twisting ofinsulated conductors 37 enables power cable 31 to be rolled onto a reel.

An elastomeric jacket 41, also of a conventional material, is extrudedaround all three of the insulated conductors 37. Jacket 41 may be eitherelectrically conductive or electrically non-conductive, and itoptionally may have longitudinally extending grooves or ridges (notshown) on its cylindrical exterior. Insulation layer 39 and jacket 41may be of a variety of conventional polymeric insulation materials.Suitable materials include the following: EPDM (ethylene propylenedienne monomer), NBR (nitrite rubber), HNB Hydrogenated Nitrile rubber,FEPM aflas rubber, FKM rubber, polypropylene (PP), polyethylene (PE)cross-linked PE or PP, thermoplastic elastomers, fluoropolymers,thermoplastics or thermoset elastomers.

Power cable 31 includes a metal band, tape or strip 43 wrapped helicallyaround jacket 41. Metal strip 43 is preferably formed of a steelmaterial, although Monel, aluminum copper or other metals are feasible.The turns of metal strip 43 overlap and preferably interlock with eachother. As shown also in FIG. 3, metal strip 43, also referred to as anarmor, may have a generally S-shaped or sinusoidal shaped configurationin cross section. Metal strip 43 has an inward facing curved valley orconcave surface 43 a that terminates in an inward facing edge 43 b,relative to power cable center line 38 (FIG. 2). Metal strip 43 has anoutward facing curved valley or convex surface 43 c that terminates inan outward facing edge 43 d. Inward and outward facing valleys 43 a, 43c join each other in a curved central transition area. The edges 43 band 43 d of one turn of metal strip 43 overlap with edges 43 b, 43 d ofadjacent turns of metal strip 43. Edges 43 b and 43 d are at oppositemargins of metal strip 43. Inward facing edge 43 b extends into and maytouch the outer surface of outward facing valley 43 c of an adjacentturn. Outward facing edge 43 d extends into and may touch the innersurface of inward facing valley 43 a of the other adjacent turn. Metalstrip 43 thus fully surrounds jacket 41.

Metal strip 43 is radially deformed from an original transverse orradial dimension prior to installation of power cable 31 in coiledtubing 29 to a smaller radial dimension. An annular gap 49 existsbetween inner diameter 51 of coiled tubing 29 and the outer diameter 53of jacket 41. After power cable 31 is installed within coiled tubing 29,annular gap 49 has a radial thickness or dimension that is less than theinitial radial dimension of metal strip 43 measured from the innermostpoint of outward facing valley 43 c to the outermost point of inwardfacing valley 43 a. The smaller dimension of annular gap 49 deformsmetal strip 43 to the same radial dimension, thereby placing metal strip43 in tight frictional engagement with coiled tubing inner diameter 51.The deformation of metal strip 43 may be elastic or permanent. Apartfrom coiled tubing 29, power cable 31 typically will not support its ownweight within an oil producing well because of the long length. Thefriction created by metal strip 43 being deformed against inner diameter51 of coiled tubing 29 is adequate to transfer the weight of power cable31 to coiled tubing 29.

Power cable 31 is formed, then installed in coiled tubing 29 whilecoiled tubing 29 is being manufactured. Power cable 31 will be formedconventionally, with metal strip 43 wrapped tightly around and infrictional engagement with jacket 41. When power cable 31 is installedduring manufacturing, coiled tubing 29 is rolled from a flat strip intoa cylindrical shape, and a weld is made of the abutting edges, as shownby weld seam 45.

FIG. 4 schematically illustrates a manufacturing process of installingpower cable 31 in coiled tubing 29 while the coiled tubing is beingmanufactured. Forming rollers 55 deform a flat plate into a cylindricalconfiguration around power cable 31 in a continuous process. Then awelding device, such as a laser torch 57, welds seam 45. Metal strip 43avoids direct contact of laser 57 with the elastomeric jacket 41, whichotherwise would create smoke. The smoke inhibits effective welding ofweld seam 45. Metal strip 43 also reduces the amount of heat received byjacket 41 from laser torch 57.

After welding, coiled tubing 29 undergoes a swaging process with swagerollers 59 to reduce the initial diameter of coiled tubing 29 to a finaldiameter. Referring to FIG. 5, before the swaging process, annular gap49 will have a greater radial thickness than afterward (FIG. 3). Theradial dimension of metal strip 43 is likewise greater before theswaging process than afterward. Before the swaging process, metal strip43 may be touching coiled tubing inner diameter 51, or there could be aslight clearance, or even some radial compression. The swaging processcauses the radial dimension of annular gap 49 (FIG. 5) to reduce to theradial dimension of annular gap 49 to that shown in FIG. 3. Thereduction in radial dimension more tightly compresses metal strip 43 toincrease the frictional engagement of metal strip 43 with coiled tubing29. During the swaging process, inward facing edges 43 b slide onoutward facing valleys 43 c. Outward timing edges 43 d slide on inwardfacing valleys 43 a. Valleys 43 a and 43 c reduce in radial dimensionduring the swaging process. The material of jacket 41 is preferably noncompressible, although jacket 41 can be deformed. The outer diameter 53of jacket 41 thus may remain constant during the swaging process.

As an example, metal strip 43 may be formed of a material having athickness in the range from 0.003 to 0.040 inch. While being radiallydeformed by the swaging process, the radial dimension of metal strip 43and gap 49 map decrease by an amount in the range from about 0.005 to0.025 inch. In this example, the swaging process thus decreases coiledtubing inner diameter 51 by an amount from about 0.010 to 0.050 inch,but it could be more.

Coiled tubing 29 is not annealed after the welding process, thus may beready for use after the swaging process. During operation of ESP 15(FIG. 1), the spaces between inward facing valleys 43 a and jacket outerdiameter 53 and the spaces between outward facing valleys 43 c andcoiled tubing inner diameter 51 provide additional room for the materialof jacket 41 to distort and flow to relieve forces resulting fromthermal expansion.

FIG. 6 illustrates an alternate embodiment in a transverse crosssection. Power cable 61 has a metal strip 63 wrapped helically aroundthe cylindrical exterior of elastomeric jacket 65. Metal strip 63 mayhave the same configuration as metal strip 43 of the first embodiment.Three electrical motor power conductors 67 are encased in jacket 65,each conductor 67 having at least one or more insulation layers 69.Conductors 67 are spaced 120 degrees apart from each other relative tothe centerline of power cable 61.

In this example, two fluid conveying tubes 71 and one signal wire tube73 are shown embedded within jacket 65. Tubes 71 and 73 extend alongsideconductors 67 the length of power cable 61. Normally, conductors 67twist relative to each other along the length of power cable 61, andtubes 71, 73 will also twist in the same manner. Tubes 71, 73 arepreferably symmetrically spaced around the centerline of power cable 61.If three tubes 71, 73 are employed, preferably they are located 120degrees apart from each other relative to the centerline of power cable61. Each tube 71, 73 is positioned between two of the conductors 67. Thecenterline or axis of each tube 71, 73 may be slightly farther from thecenterline of power cable 61 than the centerlines of conductors 67.Tubes 71, 73 optionally may be smaller in diameter than the outerdiameters of insulation layers 69. Preferably, the elastomeric materialof jacket 65 is extruded completely around each tube 71, 73. Tubes 71,73 may be formed of a metal, such as Monel.

Fluid conveying tubes 71 are hollow and employed to convey fluids toand/or from ESP 15 (FIG. 1). For example, the fluids may comprisehydraulic fluid and/or liquid chemicals employed to assist in well fluidproduction.

Signal wire tube 73 contains an instrument wire 75 for transmittingsignals to and/or from ESP 15 (FIG. 1). The signals may concern wellfluid parameter measurements, such as pressure and temperature. As anexample, instrument wire 75 may be supported in in a standoff 77 insignal wire tube 73, and the remaining portions of signal wire tube 73may be filled with an electrical insulation powder. The number of signalwire tubes 73 and fluid conveying tubes 71 may vary. In someembodiments, all of the tubes within the jacket of the power cable maycomprise signal tubes, or all may comprise fluid conveying tubes. Asingle tube within a power cable is feasible.

Power cable 61 is installed within coiled tubing 79 while coiled tubing79 is being formed and seam welded in the same manner as in the firstembodiment. Metal strip 63 will be radially deformed between jacket 65and the inner diameter of coiled tubing 79 to frictionally grip theinner diameter of coiled tubing 79. The radial dimension of metal strip65 decreases from its initial dimension while coiled tubing 79 is swagedafter being welded. Preferably, the radial deformation of metal strip 63is elastic, but it could be permanent. Metal strip 63 creates an outwardbias force against the inner surface of coiled tubing 79.

FIG. 7 illustrates another embodiment. Power cable 81 has an inner metalstrip 83, also referred to as a metal armor strip, wrapped around anelastomeric jacket 85 in the same manner as in the first twoembodiments. Inner metal strip 83 may have the same configuration asmetal strip 43 of FIG. 2. Jacket 83 is extruded around three electricalconductors 87, each having at least one insulation layer 39.

In this example, two fluid conveying tubes 91 and a signal wire tube 93form a part of power cable 81. Rather than being embedded within jacket85 as in the embodiment of FIG. 6, tubes 91, 93 are located on theexterior of inner metal strip 83. Fluid conveying tubes 91 serve toconvey fluid to and/or from ESP 15 (FIG. 1). Signal wire tube 93contains an instrument wire 95 to transmit signals to and/or from ESP15. Instrument wire 95 may be supported in a standoff 97 surrounded byan electrical insulation powder.

The number of tubes 93, 95 may vary. All of the tubes 93,95 may serve toconvey fluid, or all may serve to transmit signals. Preferably tubes 93,95 are symmetrically spaced around inner metal strip 13. In thisexample, tubes 93, 95 are spaced 120 degrees apart from each otherrelative to the centerline of power cable 81. Tubes 93, 95 are smallerin outer diameter than the outer diameter of inner metal strip 83 andoptionally may have a smaller outer diameter than the outer diameter ofinsulation layers 69.

An outer metal strip 99 wraps helically around the assembled tubes 93,95and inner metal strip 83. Outer metal strip 99 may have the sameconfiguration as metal strip 43 of the first embodiment. With threetubes 93, 95, outer metal strip 99 has a generally triangular appearancewhen viewed in the transverse cross section of FIG. 7. Outer metal strip99 has three corner portions 101, each of which extends around in tightcontact with the outer portion of one of the tubes 91, 93. Outer metalstrip 99 has intermediate portions between corner portions 101 that willcontact inner metal strip 83 at a point equidistant between two of thetubes 91, 93.

Power cable 81 is installed within coiled tubing 103 in the same manneras the other embodiments. As coiled tubing 103 is being swaged after itsseam is welded, inner surface portions of coiled tubing 103 will contactand radially deform corner portions 101 of outer metal strip 99.Initially, the transverse or radial dimension of outer metal strip 99 atcorner portions 101 is greater. The swaging process of coiled tubing 103reduces the radial dimensions at corner portions 101, causing cornerportions 101 to frictionally grip inner surface portions of coiledtubing 103. The reduction in radial thickness creates a bias force ofcorner portions 101 against inner surface portions of coiled tubing 103.The deformation may be elastic or permanent.

While the disclosure has been shown in only a few of its forms, itshould be apparent to those skilled in the art that it is not solimited, but is susceptible to various changes without departing fromthe disclosure.

The invention claimed is:
 1. An electrical submersible well pumpassembly, comprising: a pump driven by an electrical motor; a string oftubing connected to the well pump assembly and adapted to extend to anupper end of a well; a power cable installed in the tubing, the powercable comprising: three insulated electrical conductors embedded withinan elastomeric jacket; a metal strip having turns wrapped helicallyaround the jacket; the metal strip being compressed between the jacketand the tubing to cause the power cable to frictionally grip the tubing;and wherein: when viewed in a transverse cross section, each of theturns of the metal strip defines an outward facing curved valley and aninward facing curved valley, relative to a centerline of the powercable, the outward facing curved valley joining the inward facing curvedvalley at a curved transition area, each of the outward facing andinward facing curved valleys having an edge at a margin of the metalstrip; the edge of the inward facing curved valley being in contact withan outer surface of the outward facing curved valley; and the edge ofthe outward facing curved valley being in contact with an inner surfaceof the inward facing curved valley.
 2. The assembly according to claim1, wherein the metal strip is elastically deformed between the jacketand the tubing.
 3. The assembly according to claim 1, wherein prior toinstallation of the power cable in the tubing and after the metal stripis wrapped around the jacket, the metal strip has a radial dimensionbetween an inner side and an outer side that is greater than the radialdimension of the metal strip after installation of the power cable inthe tubing.
 4. The assembly according to claim 1, further comprising atleast one tube embedded within the jacket alongside the conductors andextending along a length of the power cable.
 5. The assembly accordingto claim 1, further comprising: at least one tube extending alongsideand exterior of the jacket along a length of the power cable; andwherein each turn of the metal strip extends around the tube and thejacket.
 6. The assembly according to claim 1, further comprising: ametal armor strip wrapped helically around and in physical contact withthe jacket; at least one tube extending alongside and in contact withthe metal armor strip along a length of the power cable; and whereineach turn of the metal strip extends around the tube and the metal armorstrip and is in physical contact with the tube, the metal armor stripand the tubing.
 7. An electrical submersible well pump assembly,comprising: a pump driven by an electrical motor; a string of metalcoiled tubing connected to the well pump assembly and adapted to extendto an upper end of a well; a power cable installed in the coiled tubing,the power cable comprising: three insulated electrical conductorsembedded within an elastomeric jacket, the conductors being spaced 120degrees apart from each other relative to a centerline of the powercable, the jacket having a cylindrical exterior; a metal strip havingturns wrapped helically around the jacket, the turns of the metal striphaving an inner diameter surface in contact with an outer surface of thejacket and an outer diameter surface in contact with an inner surface ofthe coiled tubing; and wherein the turns of the metal strip are radiallydeformed relative to the centerline of the power cable between the innerdiameter surface and the outer diameter surface such that the metalstrip exerts a radial inward force from the inner diameter surfaceagainst the outer surface of the jacket and an outward radial force fromthe outer diameter surface against the inner surface of the coiledtubing to cause the power cable to frictionally grip the coiled tubing.8. The assembly according to claim 7, wherein: when viewed in atransverse cross section the metal strip has a generally S-shapedconfiguration, defining an outward facing curved valley and an inwardfacing curved valley, relative to the centerline of the power cable; andthe inward facing curved valley of each turn of the metal strip overlapsthe outward facing curved valley of an adjacent one of the turns.
 9. Theassembly according to claim 7, wherein: when viewed in a transversecross section, each of the turns of the metal strip defines an outwardfacing curved valley and an inward facing curved valley, relative to thecenterline of the power cable, the outward facing curved valley joiningthe inward facing curved valley at a curved transition area, each of theoutward facing and inward facing curved valleys having an edge at amargin of the metal strip; the edge of the inward facing curved valleybeing in contact with an outer surface of the outward facing curvedvalley; and the edge of the outward facing curved valley being incontact with an inner surface of the inward facing curved valley. 10.The assembly according to claim 7, wherein the radial deformation of themetal strip is elastic.
 11. The assembly according to claim 7, furthercomprising three tubes symmetrically spaced and embedded within thejacket alongside the conductors and extending along a length of thepower cable.
 12. An electrical submersible well pump assembly,comprising: a pump driven by an electrical motor; a string of metalcoiled tubing connected to the pump assembly and adapted to extend to awellhead; a power cable electrically connected to the motor andextending through the coiled tubing for supplying power to the motor,comprising: three insulated electrical conductors embedded within anelastomeric jacket; a metal strip having turns wrapped helically aroundthe jacket, overlapping with each other, and the turns of the metalstrip having an inner diameter surface in contact with an outer surfaceof the jacket and an outer diameter surface in contact with an innersurface of the coiled tubing; the turns of the metal strip having aninitial radial thickness, relative to a centerline of the power cable,and measured from the inner diameter surface to the outer diametersurface prior to installation of the power cable in the coiled tubing;and the turns of the metal strip having a final radial thicknessmeasured from the inner diameter surface to the outer diameter surfaceafter installation of the power cable in the coiled tubing that is lessthan the initial radial thickness, so as to create a bias force from theinner diameter surface of the turns of the metal strip against the outersurface of the jacket and from the outer diameter surface of the turnsof the metal strip against the inner surface of the coiled tubing. 13.The assembly according to claim 12, wherein the metal strip iselastically deformed against the outer surface of the jacket and againstthe inner surface of the coiled tubing.
 14. The assembly according toclaim 12, wherein: when viewed in a transverse cross section, each ofthe turns of the metal strip defines an outward facing curved valley andan inward facing curved valley, relative to the centerline of the powercable, the outward facing curved valley joining the inward facing curvedvalley at a curved transition area, each of the outward facing andinward facing curved valleys having an edge at a margin of the metalstrip; the edge of the inward facing curved valley being in contact withan outer surface of the outward facing curved valley; and the edge ofthe outward facing curved valley being in contact with an inner surfaceof the inward facing curved valley.
 15. The assembly according to claim12, wherein a difference between the initial radial thickness and thefinal radial thickness of the metal strip is in the range from 0.005 to0.025 inch.